Method for Producing a Calibrated Combination of Parts

Abstract

The invention relates to a method for producing a calibrated combination (I) of parts. The combination (I) of parts comprises at least one first part (2) with a first contact surface (3) and a second part (4) with a second contact surface (5), wherein the parts (2, 4) contact each other via the contact surfaces (3, 5) in the combination (I) of parts; and the parts (2, 4) are designed to be free of an undercut at least with respect to an axial direction (6) and can be moved relative to each other along the axial direction (6) and thereby along the contact surfaces (3, 5) in the calibrated combination (I) of parts. The method has at least the following steps: a) providing the parts (2, 4) in the form of green bodies (7, 8), b) sintering the parts (2, 4) and at least forming bonded connections between the parts (2, 4); c) arranging the combination (I) of parts in a calibrating tool (IO); d) moving the parts (2, 4) relative to each other; e) arranging the parts (2, 4) in order to form the combination (I) of parts; and f) calibrating the combination (I) of parts.

Claims

1. A method for producing a calibrated parts assembly, wherein the parts assembly comprises at least a first part having a first contact surface and a second part having a second contact surface, wherein, in the parts assembly, the parts contact one another via the contact surfaces; wherein the parts are embodied in an undercut-free manner at least in relation to an axial direction and, in the calibrated parts assembly, are displaceable relative to one another along the axial direction and along the contact surfaces; wherein the method comprises at least the following steps: a) providing the first part and the second part in each case in the form of a green body, wherein a green body is produced from a pulverulent material by pressing; b) sintering the parts and at least forming materially bonded connections between the parts via the contact surfaces; c) arranging the parts assembly in a calibration tool; d) displacing the parts relative to one another along the axial direction in the calibration tool; e) arranging the parts, in order to form the parts assembly, with mutually contacting contact surfaces in the calibration tool, and f) calibrating the parts assembly by pressing and providing the calibrated parts assembly.

2. The method as claimed in claim 1, wherein prior to step a), in a step a0), in a common operation and in a common pressing tool, the parts are pressed from the pulverulent material to form a first green body and a second green body and are joined to one another in order to form the parts assembly, such that the parts contact one another via the contact surfaces; wherein the parts are provided in the form of a parts assembly in step a).

3. The method as claimed in claim 2, wherein, to form the respective green body, the first part is pressed in a first working space of the pressing tool and the second part is pressed in a second working space of the pressing tool; wherein at least one green body is displaced relative to the respectively other working space, along the axial direction, in order to form the parts assembly.

4. The method as claimed in claim 3, wherein both parts are present in the form of green bodies prior to the displacement for forming the parts assembly.

5. The method as claimed in claim 3, wherein the working spaces are arranged offset from one another along the axial direction, such that the parts do not contact one another during the pressing of at least the one part to form a green body.

6. The method as claimed in claim 2, wherein the green bodies are joined to one another in step a0) so as to form a press fit or a transition fit.

7. The method as claimed in claim 2, wherein, after the parts assembly has been formed in step a0), the parts are provided in the form of a parts assembly in step a) and are sintered in the form of a parts assembly in step b).

8. The method as claimed in claim 1, wherein the first part and the second part are produced from an identical pulverulent material.

9. A parts assembly, produced by a method as claimed in claim 1, wherein the calibrated parts assembly comprises at least a first part having a first contact surface and a second part having a second contact surface, wherein, in the parts assembly, the parts contact one another via the contact surfaces; wherein the parts are embodied in an undercut-free manner at least in relation to an axial direction and, in the calibrated parts assembly, are displaceable relative to one another at least along the axial direction and along the contact surfaces.

10. The parts assembly as claimed in claim 9, wherein, in order to produce the parts assembly, the parts are moved relative to one another exclusively along the axial direction.

11. The parts assembly as claimed in claim 9, wherein, in order to separate the parts assembly, the parts are moveable relative to one another exclusively along the axial direction.

12. The parts assembly as claimed in claim 9, wherein the parts assembly is ring-shaped, wherein each part forms a ring segment which extends along a circumferential direction.

13. The parts assembly as claimed in claim 9, wherein the parts are identical to one another in terms of their geometrical design.

Description

[0051] The invention and the technical field will be explained in more detail below on the basis of the appended figures. It is to be noted that the invention is not intended to be limited by the exemplary embodiments mentioned. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the explanatory substantive matter in the figures and to combine these with other parts and findings from the present description. In particular, it is to be noted that the figures and in particular the illustrated size ratios are only schematic. In the figures:

[0052] FIG. 1: shows a known method for producing green bodies;

[0053] FIG. 2: shows a parts assembly in a view along an axial direction;

[0054] FIG. 3: shows a perspective view of the parts assembly according to FIG. 2;

[0055] FIG. 4: shows the parts assembly according to FIG. 2;

[0056] FIG. 5: shows a perspective view of the parts assembly according to FIGS. 2 to 4 with parts that have been displaced relative to one another along the axial direction; and

[0057] FIG. 6: shows a side view of the parts assembly according to FIGS. 4 and 5.

[0058] FIG. 1 shows a method for producing green bodies 7, 8 that is known from WO 2011/035862 A1. Such a method for producing a parts assembly 1 from green bodies 7, 8 comprises pressing pulverulent materials 9 to form green bodies 7, 8, displacing/moving the green bodies 7, 8 relative to one another so as to form a press fit and thus generating the parts assembly 1.

[0059] The pressing tool 11 comprises a die 16, a first upper punch 17, a second upper punch 18, a first lower punch 19 and a second lower punch 20. According to step A of the illustrated method, the lower punches 19, 20 are displaced in the die 16 and the pulverulent material 9 is arranged. In step B, the upper punches 17, 18 are arranged in the die 16 and all punches 17, 18, 19, 20 are displaced relative to one another such that a first working space 12 and a second working space 13, comprising materials 9 that are separated from one another, are formed. In step C, the materials 9 in the working spaces 12, 13 are pressed to form the green bodies 7, 8. In step D, the green bodies 7, 8 are joined to one another by the displacement of the punches 17, 18, 19, 20. In step E, the parts assembly 1 formed by the green bodies 7, 8 is ejected.

[0060] The green bodies 7, 8 are thus firstly pressed separately in a pressing tool 11, then brought together and subsequently joined. In this case, the separated partial quantities of the pulverulent material 9 in the pressing tool 11 are pressed to form two separate green bodies 7, 8 and are brought together in the pressing tool 11 in a subsequent working step. During the pressing of the green bodies 7, 8, the punches 17, 19 of the adjacent working space 12 form a working space 13 for the respectively other green body 8. A punch 17, 19 arranged in the center of the pressing tool 11 may in this case form a cavity in a second working space 13 surrounding these punches 17, 19, such that the first green body 7 generated in the first working space 12 may be introduced into this cavity during the joining. The outer punches 18, 20 form the outer second working space 13 for the second green body 8.

[0061] FIG. 2 shows a parts assembly 1 in a view along an axial direction 6. FIG. 3 shows a perspective view of the parts assembly 1 according to FIG. 2. FIG. 4 shows the parts assembly 1 according to FIG. 2. FIG. 5 shows a perspective view of the parts assembly 1 according to FIGS. 2 to 4 with parts 2, 4 that have been displaced relative to one another along the axial direction 6. FIG. 6 shows a side view of the parts assembly 1 according to FIGS. 4 and 5. FIGS. 2 to 6 will be described jointly below.

[0062] The calibrated parts assembly 1 comprises a first part 2 having a first contact surface 3 and a second part 4 having a second contact surface 5, and also a third part 21, wherein, in the parts assembly 1, the parts 2, 4, 21 contact one another via the contact surfaces 3, 5. The parts 2, 4, 21 are each of identical embodiment. The parts 2, 4, 21 are embodied in an undercut-free manner in relation to an axial direction 6 and can, in the calibrated parts assembly 1, be displaced relative to one another only along the axial direction 6 and along the contact surfaces 3, 5.

[0063] The parts 2, 4, 21 are provided with geometrical structures (in the manner of a so-called dovetail connection in this case) which, in relation to a radial direction 22 and a circumferential direction 14, bring about a form-fitting connection of the parts 2, 4, 21. The parts assembly 1 is of ring-shaped embodiment, wherein each part 2, 4, 21 forms a ring segment which extends along the circumferential direction 14.

[0064] In the course of the method, in step a0), in a common operation and in a common pressing tool 11, a first green body 7 and a second green body 8 (and also a third green body) are generated from the pulverulent material 9 by pressing (see FIG. 1, steps A, B, C). The three green bodies 7, 8 are joined to one another in order to form the parts assembly 1 (see FIG. 1, step D), such that the green bodies 7, 8 (or parts 2, 4, 21) contact one another via the contact surfaces 3, 5. The thus produced parts 2, 4, 21 are provided in the form of a parts assembly 1 in step a) (see FIG. 1, step E and FIGS. 2 and 3).

[0065] According to step a), the parts 2, 4, 21 are provided in each case in the form of a green body 7, 8, wherein a green body 7, 8 is produced from a pulverulent material 9 by pressing. According to step b), the parts 2, 4, 21 are sintered and materially bonded connections are formed between the parts 2, 4, 21 via the contact surfaces 3, 5 (for example FIGS. 2 and 3). According to step c), the parts assembly 1 is arranged in a calibration tool 10. According to step d), the parts 2, 4, 21 are displaced relative to one another along the axial direction 6 in the calibration tool 10 (see FIGS. 4 to 6; calibration tool for example designed as per pressing tool 11 according to FIG. 1; only indicated in FIGS. 4 to 6). According to step e), the parts 2, 4, 21 are arranged, in order to form the parts assembly 1, with mutually contacting contact surfaces 3, 5 in the calibration tool 10 (for example as per FIGS. 2 and 3), and according to step f), the parts assembly 1 is calibrated by pressing and the calibrated parts assembly 1 is provided (for example as per FIGS. 2 and 3).

[0066] The contact surfaces 3, 5 of the parts 2, 4, 21 extend exclusively in planes which run parallel to the axial direction 6. The parts 2, 4, 21 are embodied such that they can be displaced relative to one another along the axial direction 6, wherein the parts 2, 4, 21 slide against one another via the contact surfaces 3, 5. For this purpose, the parts 2, 4, 21 are embodied in an undercut-free manner, that is to say the parts 2, 4, 21 can be displaced relative to one another along the axial direction 6 in an uninhibited manner.

[0067] In step d), the parts 2, 4, 21 are displaced relative to one another along the axial direction 6. The parts 2, 4, 21 are displaced relative to one another by various components of the calibration tool 10 (for example by one or more lower punches 19, 20/one or more upper punches 17, 18; see for example FIG. 1). As a result of the displacement, the connections generated in step b) between the contact surfaces 3, 5 of the parts 2, 4, 21 are broken. In this case, the parts 2, 4, 21 are displaced to such an extent along the axial direction 6 that the mutually contacting contact surfaces 3, 5 still have an overlap 23 of at least 25% along the axial direction 6 (see FIGS. 4 to 6), compared with an overlap 23 of 100% of the contact surfaces 3, 5 in the arrangement provided for the parts assembly 1 (see FIGS. 2 and 3).

[0068] In step e), the parts 2, 4, 21 are displaced (back) again and in particular positioned relative to one another in the arrangement provided by the parts assembly 1. However, the arrangement of the parts 2, 4, 21 according to step b) and step e) may also differ from one another.

[0069] In step f), the parts 2, 4, 21 or the parts assembly are/is calibrated. A subsequent pressing operation is effected here, in particular to increase the dimensional accuracy. In particular, this involves plastically deforming the parts 2, 4, 21 or the parts assembly 1.

LIST OF REFERENCE DESIGNATIONS

[0070] 1 Parts assembly [0071] 2 First part [0072] 3 First contact surface [0073] 4 Second part [0074] 5 Second contact surface [0075] 6 Axial direction [0076] 7 First green body [0077] 8 Second green body [0078] 9 Material [0079] 10 Calibration tool [0080] 11 Pressing tool [0081] 12 First working space [0082] 13 Second working space [0083] 14 Circumferential direction [0084] 15 Pressing direction [0085] 16 Die [0086] 17 First upper punch [0087] 18 Second upper punch [0088] 19 First lower punch [0089] 20 Second lower punch [0090] 21 Third part [0091] 22 Radial direction [0092] 23 Overlap